3-Bromoacetyl-6,7-methylenedioxycoumarin as a Highly Reactive and Sensitive Fluorescence Labeling Reagent for Fatty Acids

Abstract

Keywords3-Bromoacetyl-6,7-methylenedioxycoumarin, fatty acid, fluorescence labeling reagent, high-performance liquid chromatographyCoumarin derivatives have been known to be useful labeling reagents owing to their strong fluoroscence in solution, suitable molecular size, easy synthesis and good storage. Of these coumarins, 4-bromomethyl-7-acetoxy-1, 4-bromomethyl-6,7-dimethoxy-(BrDMC)2, and 4-bromomethyl-6,7-methylenedioxy-coumarins (BrMDC)3 were listed as highly sensitive reagents for carboxylic acids, which were mostly comparable in sensitivities or quantum yields to other reagents, e.g., 1-bromoacetylpyrene4, 3-bromomethyl-6,7-dimethoxy-lmethyl-2(1 H)-quinoxaline5, 9-anthryldiazomethane6, p-(9-anthroyloxy)phenacyl bromide', 9,10-diaminophenanthrene8, 9-aminophenanthrene9, and monodansyl cadaverine,lo Thus, 3-bromoacetyl-6,7-methylenedioxycoumarin (BrAMDC, Fig. 1) was sythesized in a search for the most excellent reagent regarding both reactivity and sensitivity among coumarins for carboxylic acids analysis. Free fatty acids in human blood plasma were readily labeled with BrAMDC under quite mild conditions. Experimental ApparatusProton nuclear magnetic resonance (1H-NMR) spectra were obtained with a JEOL JNM-GSX 500FT-NMR spectrometer employing tetramethylsilane as an internal standard. Absorption and fluorescence spectra were measured with a Hitachi 150-20 spectrophotometer and a Hitachi F-4000 fluorescence spectrophotometer, respectively. The fluorescence quantum yields were determined according to the method of Paker and Rees11, quinine sulfate in 0.5 M H2SO4 was used as a standard. Mass spectra were taken with a JEOL JMS-DX303 spectrometer. A Hitachi 655A high-performance liquid chromatograph was used, equipped with a Hitachi F-1050 fluorescence spectrophotometer (excitation wavelength 388 nm; emission wavelength 475 nm) and a Hitachi L-6200 solvent gradient device. A Unisil Pack 5C18-250A column (250X4.6 mm i.d.; particle size, 5 µm;

Improvement of Fluorescence Characteristics of Coumarins: Syntheses and Fluorescence Properties of 6-Methoxycoumarin and Benzocoumarin Derivatives as Novel Fluorophores Emitting in the Longer Wavelength Region and Their Application to Analytical Reagents

“…30) Crude product was subjected to silica gel chromatography using chloroform as the eluent and recrystallized from hexane to give 1b as pale yellow needles. 3-Bromoacetyl-6-methoxycoumarin (2a): This compound was prepared by the bromination of acetyl compound 1c using tetrabuthylammonium tribromide (TBABr 3 ) as previously reported 46,47) and recrystallized from ethanol to give yellow needles of 2a. General Synthetic Method of Derivatized Products 2b-d 46,47) A mixture of 2a (1.1 mmol), the appropriate carboxylic acid (1.2 mmol), 18-crown-6 (1.0 mmol), and KHCO 3 (800 mg) in acetone (200 ml) was stirred at room temperature for 30 min.…”

“…The synthetic route for the above derivatization reagents and their derivatization reactions are shown in Chart 1. One reagent, 2a with a bromoacetyl-reactive group, was synthesized from 1d as previously reported, 46,47) and the derivatization reaction of carboxylic acids with 2a was carried out using acetic acid, lauric acid, and benzoic acid as model carboxylic acids in the presence of catalysts such as KHCO 3 and 18-crown-6 to yield the derivatized compounds 2b-d, respectively. Another reagent, 3a with a carboxylic group as a reactive group, was synthesized by the acid hydrolysis of 1c, and the derivatized compounds esters 3b and c and amides 3d-f were obtained using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC HCl) and 4-N,N-dimethylaminopyridine (DMAP) as usual catalysts in dichloromethane.…”

Determination of long-chain fatty acids in bryophyte plants extracts by HPLC with fluorescence detection and identification with MS

“…Therefore, derivatization of these analytes with labeling reagents, especially for the fluorescence detection, has been widely adopted. These reagents commonly used include coumarin-type derivatives [9][10][11][12][13][14][15][16]; diazomethane-type reagents such as 9-anthryldiazomethane (ADAM) [17,18] and 1-pyrenyldiazomethane (PDAM) [19]; quinoxalinone derivatives [20][21][22][23]; benzofurazan-type reagents [24][25][26]; sulfonate ester reagents such as 2-(2-naphthoxy)-ethyl-2-(piperidino)-ethanesulfonate (NOEPES) [27], 2-(2,3-naphthalimino)-ethyl trifluoromethane-sulfonate (NE-OTF) [28] and 2-(2,3-anthracene -dicarboximido) ethyl trifluoromethanesulfonate (AE-OTF) [29]; benzohydrazide-type reagents such as 4-(1-methylphenanthro [9,10-d]imidazole-2-yl)benzohydrazide (MPIB-hydrazide) [30] and 4-(5,6-Dimethoxy-2-benzimidazoyl)-benzohydrazide) (DMBI-hydrazide) [31] and so on. However, it has been reported that these reagents have limitations in their applications, such as short detection wavelengths, poor stability, low detection sensitivity, tediously analytical procedure, and serious interferences in the biological sample analyses [32].…”

Determination of Free Fatty Acids in Soil and Bryophyte Plants by Precolumn Derivatization via HPLC with Fluorescence Detection and Tandem Mass Spectrometry (HPLC‐MS/MS)

“…Therefore, derivatization of these analytes with labeling reagents has been widely adopted since HPLC with UV, especially fluorescence detection, has higher sensitivity. These reagents commonly used include coumarin type derivatives, [10] - [16] diazomethane-type reagents such as 9-anthryldiazomethane (ADAM) [17] - [18] and 1-pyrenyldiazomethane (PDAM), [19] quinoxalinone derivatives. [20] - [22] benzofurazan-type reagents, [23] - [25] sulfonate ester reagents 2-(2-naphthoxy)-ethyl-2-(piperidino)-ethanesulfonate Y.…”